The Queen received an Oyster card from the visit. Credit: Chris Radburn/PA Archive

Sheikh Khalifa bin Zayed, president of the United Arab Emirates, presented the Queen with a gold jewelled frame set on a jewelled ostrich egg and a five-strand necklace, made from natural pearls sourced from the Arabian Gulf, when he visited the UK last April.

Prince Harry listens to First Lady Michelle Obama at the White House. Credit: John Stillwell/PA Archive

Harry was in the US last May to support the Warrior Games - a Paralympic-style sporting event for wounded servicemen and women - and also visited the White House during his trip.

Charles and Camilla toured the Middle East last March and the Prince was given 12 bottles of olive oil from Jordan's Princess Alia, a member of the country's royal family, who also gave the Duchess a box of toiletries.